1. Field of the Invention
The present invention relates generally to a weatherstrip structure for an automotive vehicle. More specifically, the present invention relates to a weatherstrip structure for an automotive vehicle which can provide a highly reliable sealing effect at a vehicle body opening edge, i.e. between inside and outside of a vehicle body.
2. Description of the Background Art
A weatherstrip for sealing a space between, such as, a vehicle body opening edge and a trunk lid, is disclosed such as in U.S. Pat. No. 4,848,035 issued on Jul. 18, 1989.
In this background art, the weatherstrip includes an elongate main body made of a solid rubber. The main body includes an elongate upper section and a pair of elongate side sections facing each other so as to have a substantially reversed U-shaped cross-section. First and second grasping lips are provided extending inward from the corresponding opposite side sections at vertically intermediate positions thereof for holding therebetween an upright flange provided at the vehicle body opening edge. Specifically, the first grasping lip extends from one of the side sections located inside the vehicle body with respect to the flange (hereinafter referred to as "inside section"), while, the second grasping lip extends from the other of the side sections located outside the vehicle body (hereinafter referred to as "outside section"). A third grasping lip is further provided extending inward from the inside section at a vertical position lower than the first grasping lip.
A seesaw lip is further provided at a lower end of the outside section and connected thereto through a linkage section. The linkage section is formed thinner in width than the other portions of the outside section. Specifically, the seesaw lip has a grasping lip section extending inward from the linkage section and a sub-lip section extending outward from the linkage section substantially in a direction opposite to that of the grasping lip section. The first to third grasping lips and the seesaw lip are made of the same material as the main body except for an outward tip of the seesaw lip, i.e. a tip of the sub-lip section. The tip of the sub-lip is made of sponge rubber (rubber foam) other than the solid rubber.
When the weatherstrip is depressed to receive the upright flange therein, the flange is grasped under pressure between the first and second grasping lips and between the third grasping lip and the grasping lip section of the seesaw lip so that the weatherstrip is firmly retained on the upright flange. Further, during the insertion of the upright flange into the weatherstrip, the seesaw lip is arranged to pivot or tilt with the linkage section working as a fulcrum. Accordingly, assembling of the weatherstrip onto the upright flange is facilitated. Simultaneously, the pivotal or tilting movement of the seesaw lip allows the sub-lip section to pivot inward until the sponge rubber tip of the sub-lip is pressed against a planar surface which is an outward extension from the upright flange and arranged substantially in perpendicular to the upright flange, so as to ensure a sealing effect therebetween.
On the other hand, since the seesaw lip is rather easily pivoted using the linkage section as the fulcrum, it is likely that the seesaw lip is tilted excessively during assembling of the weatherstrip onto the upright flange. This excessive pivotal movement of the seesaw lip causes less pressure applied between the grasping lip section of the seesaw lip and the upright flange, and further causes the sponge rubber tip of the sub-lip section to partially bend or turn up inward so as to generate small gaps between the outward extension of the flange and the sponge rubber tip of the sub-lip section. Accordingly, the sealing effect provided by the grasping lip section and the sub-lip section of the seesaw lip inevitably becomes significantly less to allow invasion of water and dust into the vehicle body.
Further, since the grasping lip section of the seesaw lip is made of the solid rubber having a relatively high rigidity, the inward tip of the grasping lip section can not precisely follow configuration of an outer surface of the upright flange against which the inward tip of the grasping lip section is pressed. For example, when a difference in level or a step is formed on the outer surface of the upright flange due to superposition of another flange at a joint portion therebetween, or a seal paint is applied to the above-noted stepped portion to provide a rugged surface thereon, the inward tip of the grasping lip section can not precisely follow such a configuration on the outer surface of the upright flange so that gaps are generated therebetween to allow invasion of water and dust into the vehicle body.